Moist wood and other cellulosic organic products which are kept in stationary air, for instance in limited spaces (rooms), in closed constructions, in piles or stacks is attacked by microorganisms, particularly fungi of various kinds. They discolor the wood and also give in other respects a less desirable appearance. Some of these fungi, especially mold, are difficult to control or eliminate. The attacks are to a high degree dependent on the temperature and the kind of fungi. Below 5.degree. C. there are few attacks and around 45.degree. C. and above only a few fungi can develop. Generally, the most severe fungi attacks occur at temperatures of around 25.degree. to 30.degree. C. Such fungi thrive in remote spaces with low air circulation and with relatively high moisture and temperatures. In such areas it is also most difficult to have contact with and treat the wood against the fungi.
The problem may simply be so defined that it is of importance to protect the wood (as long as it is moist) until it has been dried and no risk of fungi attacks is present.
In order to prevent the development of these fungi, above all the troublesome mold, many different kinds of treatments have been used. High amounts of preservative have been required to obtain satisfactory results. One method that has been successful and is of interest in connection with the present innovation has been to treat the wood with solutions of alkali metal hydroxides or sodium carbonate. Extensive experiments with alkali treatment of such products as wood chips have been published over the past 20 years. Good effects have been obtained.
During these experiments it has been observed that it is an advantage not to use alkalies of excessive strength, as these may attack the wood fibers, especially as the treated products become drier.